Earticle

Snailshells and discarded aluminium based alloys have low economic values and are mostly considered as environmental pollutants. However, recycling them for further application in material processing can create significant economic value. Snailshell particles are known for their hardness, and thus useful as good alloying element for aluminium based pistons. In this paper, the potential of snailshell particles as reinforcement agent in Al/snailshell particulate composites is reported. Snailshell particles of weight fraction ranging from 16 to 48 wt.% and size of 200, 400 and 600 μm were added to aluminium obtained from discarded aluminum pistons during casting. The microstructures of the composites were examined under optical metallurgical microscope. The tensile strength and hardness were measured based on the experiments conducted using Box Behnken design. The results showed that, at 48 wt.% and 600 μm particle size, the tensile strength and hardness are maximum (236 MPa and 48.3 HRF, respectively) compared to the tensile strength of 92.4 MPa and hardness of 29.2 HRF for the unalloyed samples. These increments are attributed to the uniform distribution of snailshells in the ductile aluminum matrix. It is concluded that both the tensile strength and hardness are significantly enhanced, and snailshells can be used as a low-cost reinforcement for engineering applications.

Delays at the signalized intersections the most important parameters of the signal timing optimization and level of service (LOS) estimations. The determination of the delays at the signalized intersections has a significant importance for the evaluation of the performance and travel time of the transportation modes. The optimization of the travel time delays at the signalized intersections provides a better fuel economy. This study compared these delays in the scope of the various model studies in Turkey and other countries considering the signalized intersection approaches controlled in fixed-time and operated in a range of conditions. This study also specifically focused on the differences between Iran and Turkey considering the modal approaches and the driver behavior variations.

Demolition waste is waste debris from destruction of a construction. Construction industry in India generates about 10-12 million Tons of waste annually. While Retrievable items like bricks, wood, metal, titles are recycled in India, Concrete and masonry waste (>50% of total waste) are not recycled. A defined manual is not available with regulatory authorities for effective management of Construction and Demolition (C & D) waste. Authorities sometimes make rules but often fail in implementing them. This report is expected to be a pilot study towards preparation of such a manual. The objective of this study is to compile relevant literature which will give an insight into demolition waste management strategies of different countries and role of regulatory authorities in demolition waste management. The paper also studies the properties of demolition waste, its hazardous effects and suggests safe recycling/reuse/disposal methods. Based on the study, A C & D Waste management plan was formulated. For effective use of C & D, it essential that the local governing bodies make the submission and implementation of this plan mandatory. This would go a long way in the reduction of Environmental Pollution due to Construction and Demolition waste.

Generally, the 3D visualization simulation includes the 3D entity model, virtual environment and physical data field (including electromagnetic field and underwater acoustic field). In order to improve the flexibility and scalability of the model or simulation, and effectively solve the contradiction between simulation complexity and the limited resources, we propose the multi-resolution modeling (MRM) method of 3D visualization simulation based on meta-model. The paper firstly learns from the simulation soft FLAMES (the Flexible Analysis Modeling and Exercise System). Based on the simulation framework of behavior modeling and object-oriented, we design the reference frame of meta-modeling for 3D visualization simulation. Then, the meta-model can be formally described by using the BNF (Backus-Naur Form). Finally, we realize the multi-resolution modeling by using the different levels of detail.

Header compression increases efficiency. Further increase in efficiency is obtained by differential header compression. But subsequent packets have to be discarded if the context is not synchronized in differential header compression. Many algorithms had been proposed earlier to reduce discarding of subsequent packets. One of the basic techniques is use of reference value through which packets are encoded and decoded in compressor and decompressor respectively. Major disadvantage of this technique is that if the reference value is lost or erroneous then receiver cannot decompress the packets correctly. We have addressed this problem in the proposed scheme. In the proposed scheme even if the reference value or packets are lost or erroneous, receiver can regenerate the reference value and the packets. We have also shown that the proposed scheme has low average delay in high packet error rate and also works well in long round trip time. Some level of burst error is also handled by the proposed scheme.

The life prediction method based on the power spectral envelope energy and Support Vector Machine (SVM), which is the combination of time-domain and frequency-domain, is proposed for the key component of aircraft’s (aircraft air refrigerator) life unpredictable problems. By first, made a long-term test for aircraft air refrigerator through aircraft-specific life testing platform, then got a lot of acceleration parameters which characterize the health status of the aircraft air refrigerator. Through the analysis of acceleration parameters’ power spectrum, its power spectrum envelope energy would be obtained. Used the power spectrum envelope energy to construct feature vector, and designed SVM life prediction model and using this model to predict aircraft air refrigerator’s lifetime. The research results show that the life prediction method based on the power spectral envelope energy and SVM can achieve a good life prediction of aircraft air refrigerator, and laid the foundation for life prediction of air refrigerator in aircraft engineering application.